#include <iostream>
#include <stdlib.h>
#include <unistd.h>

class Task
{
public:
    Task(int x , int y)
    :x_(x),y_(y)
    {}

    void operator()()
    {
        int ret = x_ + y_;

        std::cout  << " : did a task , the ret is : " << ret << std::endl;
        usleep(3000);
    }

private:
    int x_ ; 
    int y_ ;
};
